Graphene has rapidly received significant attention since its discovery in 2004 due to its unique electrical, mechanical, and physical properties. Examples of such include low resistivity and high carrier mobilities. Researchers have discovered, for example, that electrons can travel substantially faster in graphene than in silicon by approximately one hundred times due to graphene's low resistivity. A single-atom-thick sheet of graphite, for instance, provides a resistivity of about 1.0 micro-Ohm per cm, which is approximately 35% less than the resistivity of copper, the previously lowest resistivity material known at room temperature. This low resistivity in graphene therefore provides higher conductivity for graphene-based applications, which is a big advantage for semiconductor applications that require rapid switching.
Regarding carrier mobility, graphene's limit to mobility of electrons also surpasses silicon. The limit of electron mobility in graphene is set by thermal vibration of the atoms and is approximately 200,000 cm2/Vs at room temperature. Silicon, on the other hand, is about 1400 cm2/Vs. Because current graphene applications utilize only 10,000 cm2/Vs, potential exists to maximize graphene-based applications to attain the 200,000 cm2/Vs limit.
Despite these advantages, graphene is usually constructed with channels having a nanoscale line width. Thus, to take advantage of these graphene-based applications, graphene fabrication generally requires the production of nanowires with a line width of approximately 1-2 nm in order to have a silicon band gap (i.e., approximately 1.11 eV). This causes problems because presently available semiconductor processing techniques make it impossible to cut graphene to such a narrow nanoscale line width, which is typically less than 3 nm. Additionally, conventional methods are much slower, requiring each point to be etched away by electrochemically reacting in a serial fashion. Further, these conventional methods typically rely on etching through a mask that has been fabricated using top-down lithography, which is known for preventing nanoscale resolution of patterns.
Therefore, what is needed is a new method for fabricating graphene at a nanoscale. The preferred method would be faster, utilizes a “bottom-up” approach, and uses DNA samples for etching.